  /* 以下五项为顶部菜单的通用设置 */
  #header {
    position: fixed;
    top: 0px;
    left: 0px;
    background-color: black;
    width: 100%;
    height: 65px;
    color: white;
    text-align: center;
    font-size: 5mm;
}

#header div {
    float: left;
    height: 35px;
    margin-left: 25px;
    line-height: 35px;
}

#header input {
    line-height: 25px;
    font-size: 5mm;
}

#header_div_nav li div:hover,
#header button:hover,
#header_div_menu span:hover {
    color: teal;
    cursor: pointer;
}

#header button {
    background-color: black;
    color: white;
    font-size: 5mm;
}

/* 当页面宽度足够大时，集成菜单不显示 */
#header_div_nav,
#header_div_menu ul {
    list-style: none;
}

/* 下面是基层菜单的格式设置 */
#header_div_nav li div {
    margin-left: 5px;
    width: 100px;
    text-align: center;
    font-size: 6mm;
}

#header_div_menu {
    position: absolute;
    right: 50px;
}

#header_div_menu span {
    display: inline-block;
    height: 150px;
}

#header_div_menu li {
    position: relative;
    left: 47px;

}

#header_div_menu li div {
    background-color: black;
    width: 55px;

}

/* 给顶部集成菜单按钮的子项添加上小手 */
#header_div_menu li div:hover {
    color: teal;
    cursor: pointer;
}

/* 调整顶部集成按钮的子项的位置 */
#header_div_menu li:first-child {
    margin-top: 50px;
}

/* 遮蔽层 */
.overlay {
    position: absolute;
    top: 0px;
    left: 0px;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 102;

}

/* 登陆窗口 */
#header_popupwindow_login {
    border: 2px black solid;
    width: 320px;
    height: 120px;
    text-align: center;
    position: absolute;
    top: 100px;
    left: 50%;
    margin-left: -160px;
    font-size: 6mm;
    background: black;
    color: white;
    z-index: 103;

}

/* 注册窗口 */
#header_popupwindow_regist {
    border: 2px black solid;
    width: 320px;
    height: 240px;
    font-size: 6mm;
    position: absolute;
    top: 100px;
    left: 50%;
    margin-left: -160px;
    background: black;
    color: white;
    z-index: 103;

}

/*弹出窗口的表格格式*/
.popwin {
    margin: 10px auto;
    text-align: center;
}

/* 调整弹出窗口的表格的行间距 */
.popwin td {
    padding-top: 10px;
}

/* 调整集成菜单按钮的子项的位置 */
.top_vertical_play {
    position: relative;
    top: 50%;
    margin-top: -17px;
}

/* 绑定操作，当鼠标移动到集成菜单按钮时，显示子菜单 */
.top_menu:hover .top_menu_item {
    display: block;
}

/* 隐藏顶部集成菜单的子项 */
.top_menu_item {
    display: none;
}